Détails:A Lockheed C-130 Hercules Coast Guard plane was destroyed in an accident following a mid-air collision with a US Marine Corps Bell AH-1W Super Cobra. The Cobra helicopter was on a training mission out of Camp Pendleton with two crew. The C-130 (CG 1705) took off from Sacramento-McClellan AFB, CA (MCC) at about 15:30 as part of a search for a skiff with one person aboard that had been reported missing for two days. The search and rescue (SAR) mission was carried out in the vicinity of San Clemente Island off the California coast. The search pattern took CG 1705 in and out of airspace Warning Area 291 (W-291). A flight of four USMC helicopters also were operating in W-291. The flight consisted of two Sikorsky CH-53E Super Stallion transport helicopters and two Bell AH-1W Super Cobra attack helicopters. All aircrew wore night vision goggles. The Cobra's were briefed to fly at 300 feet of step-up (800 feet altitude)at the 5 and 7 o'clock positions of the two CH-53s. The mishap Cobra had its anticollision light and IFF transponder switched off. In order to increase separation from another military flight in the area, the formation of four initiated a right-hand turn while climbing to approximately 1000 ft. This brought the helicopters in the flight path of the Coast Guard C-130 and a collision occurred.

Debris was found and the Coast Guard suspended the search for survivors at 09:50, Nov. 1.

No single factor or individual act or omission caused this mishap. It was the product of a tragic confluence of events, missed opportunities, and procedure/policy issues in an airspace where most aircraft fly under a "see-and-avoid" regime (i.e. where individual aircraft de-conflictthemselves).a contributing factor to this mishap was that FACSFAC San Diego did not provide operational priority to CG 1705.